Immuno-histological detection of resistant columnar units and vulnerable networks in the rat retina after asphyxia-induced transient cardiac arrest.

BACKGROUND: Stroke-related loss of vision is one of the residual impairments, restricting the quality of life. However, studies of the ocular manifestations of asphyxia cardiac arrest/resuscitation (ACA/R) have reported very heterogeneous results. OBJECTIVE: We aimed to evaluate the ACA/R-induced degeneration pattern of the different retinal cell populations in rats using different immuno-histological stainings. METHODS: The staining pattern of toluidine blue and the ganglion cell markers ß-III-tubulin and NeuN; the calcium-binding protein parvalbumin, indicating ganglion, amacrine, and horizontal cells; calretinin D28k, indicating ganglion and amacrine cells; calbindin, indicating horizontal cells; Chx 10, indicating cone bipolar cells; PKCα, indicating ON-type rod bipolar cells; arrestin, indicating cones; and rhodopsin, a marker of rods, as well as the glial cell markers GFAP (indicating astroglia and Müller cells) and IBA1 (indicating microglia), were evaluated after survival times of 7 and 21 days in an ACA/R rat model. Moreover, quantitative morphological analysis of the optic nerve was performed. The ACA/R specimens were compared with those from sham-operated and completely naïve rats. RESULTS: ACA/R-induced effects were: (i) a significant reduction of retinal thickness after long-term survival; (ii) ganglion cell degeneration, including their fiber network in the inner plexiform layer; (iii) degeneration of amacrine and cone bipolar cells; (iv) degeneration of cone photoreceptors; (v) enhanced resistance to ACA/R by rod photoreceptors, ON-type rod bipolar and horizontal cells, possibly caused by the strong upregulation of the calcium-binding proteins calretinin, parvalbumin, and calbindin, counteracting the detrimental calcium overload; (vi) significant activation of Müller cells as further element of retinal anti-stress self-defense mechanisms; and (vii) morphological alterations of the optic nerve in form of deformed fibers. CONCLUSIONS: Regardless of the many defects, the surviving neuronal structures seemed to be able to maintain retinal functionality, which can be additionally improved by regenerative processes true to the "use it or lose it" dogma.

The Spinal Cord Damage in a Rat Asphyxial Cardiac Arrest/Resuscitation Model.

BACKGROUND: After cardiac arrest/resuscitation (CA/R), animals often had massive functional restrictions including spastic paralysis of hind legs, disturbed balance and reflex abnormalities. Patients who have survived CA also develop movement restrictions/disorders. A successful therapy requires detailed knowledge of the intrinsic damage pattern and the respective mechanisms. Beside neurodegenerations in the cerebellum and cortex, neuronal loss in the spinal cord could be a further origin of such movement artifacts. METHODS: Thus, we aimed to evaluate the CA/R-induced degeneration pattern of the lumbar medulla spinalis by immunocytochemical expression of SMI 311 (marker of neuronal perikarya and dendrites), IBA1 (microglia marker), GFAP (marker of astroglia), calbindin D28k (marker of the cellular neuroprotective calcium-buffering system), MnSOD (neuroprotective antioxidant), the transcription factor PPARγ and the mitochondrial marker protein PDH after survival times of 7 and 21 days. The CA/R specimens were compared with those from sham-operated and completely naïve rats. RESULTS & CONCLUSION: The main ACA/R-mediated results were: (1) degeneration of lumbar spinal cord motor neurons, characterized by neuronal pyknotization and peri-neuronal tissue artifacts; (2) attendant activation of microglia in the short-term group; (3) attendant activation of astroglia in the long-term group; (4) degenerative pattern in the intermediate gray matter; (5) activation of the endogenous anti-oxidative defense systems calbindin D28k and MnSOD; (6) activation of the transcription factor PPARγ, especially in glial cells of the gray matter penumbra; and (7) activation of mitochondria. Moreover, marginal signs of anesthesia-induced cell stress were already evident in sham animals when compared with completely naïve spinal cords. A correlation between the NDS and the motor neuronal loss could not be verified. Thus, the NDS appears to be unsuitable as prognostic tool.

Normoxic post-ROSC ventilation delays hippocampal CA1 neurodegeneration in a rat cardiac arrest model, but does not prevent it.

The European Resuscitation Guidelines recommend that survivors of cardiac arrest (CA) be resuscitated with 100% O2 and undergo subsequent-post-return of spontaneous circulation (ROSC)-reduction of O2 supply to prevent hyperoxia. Hyperoxia produces a "second neurotoxic hit," which, together with the initial ischemic insult, causes ischemia-reperfusion injury. However, heterogeneous results from animal studies suggest that normoxia can also be detrimental. One clear reason for these inconsistent results is the considerable heterogeneity of the models used. In this study, the histological outcome of the hippocampal CA1 region following resuscitation with 100% O2 combined with different post-ROSC ventilation regimes (21%, 50%, and 100% O2) was investigated in a rat CA/resuscitation model with survival times of 7 and 21 days. Immunohistochemical stainings of NeuN, MAP2, GFAP, and IBA1 revealed a neuroprotective potency of post-ROSC ventilation with 21% O2, although it was only temporary. This limitation should be because of the post-ROSC intervention targeting only processes of ischemia-induced secondary injury. There were no ventilation-dependent effects on either microglial activation, reduction of which is accepted as being neuroprotective, or astroglial activation, which is accepted as being able to enhance neurons' resistance to ischemia/reperfusion injury. Furthermore, our findings verify the limited comparability of animal studies because of the individual heterogeneity of the animals, experimental regimes, and evaluation procedures used.

Relative Resilience of Cerebellar Purkinje Cells in a Cardiac Arrest/Resuscitation Rat Model.

BACKGROUND: In studies on cardiac arrest (CA)/resuscitation (R) injury, Purkinje cell degeneration was described, however, with inconsistent data concerning severity and time point of manifestation. Moreover, CA/R studies paid only limited attention to inhibitory stellate interneurons. To this aim, the hypothesis that cerebellar could be relatively resilient toward CA/R because of diverse cellular defense mechanisms including interaction with stellate cells was tested. METHODS: We examined rats with survival times of 6, 24, and 48 h, and 7 and 21 days in comparison with sham- and nonoperated animals. Thereby, we focused on the immunohistochemical expression of cfos, MnSOD, Bcl2, caspase 3, parvalbumin, calbindin D28 k, MAP2, IBA1, and GFAP, especially in the particular sensitivity to CA/R cerebellar lobule IX. Hippocampal CA1 degeneration was demonstrated by expression patterns of MAP2 and NeuN in combination with IBA1 and GFAP. RESULTS/CONCLUSIONS: Comparative analysis of hippocampal CA1 pyramidal cells and cerebellar Purkinje cells confirmed a relative resil-ience of Purkinje cells to CA/R. We found only a notable degeneration of Purkinje cell neuronal fiber network, which, however, not necessarily led to neuronal cell death. To induce significant Purkinje cell loss, a stronger ischemic trigger seems to be needed. As possible Purkinje cell-protecting mechanisms, we would propose: (1) activation of inhibitory stellate cells, shown by cfos, MnSOD, and Bcl2 expression, balancing out ischemia-induced excitation and inhibition of Purkinje cells; (2) translocation of the calcium-buffering system, shown by parvalbumin and calbindin D28 k expression, protecting Purkinje cells from detrimental calcium overload; (3) activation of the neuron-astrocyte cross talk, protecting Purkinje cells from over-excitation by removing potassium and neurotransmitters from the extracellular space; (4) activation of the effective and long-lasting MnSOD defense system; and (5) of the anti-apoptotic protein Bcl2 in Purkinje cells itself. Moreover, the results emphasize the limited comparability of animal CA/R studies because of the heterogeneity of the used experimental regimes.

Independent Predictors for Higher Postoperative Pain Intensity During Recovery After Open Thoracic Surgery: A Retrospective Analysis in 621 Patients.

Objective: To evaluate two standard procedure-specific pain regimens and to assess independent predictors for higher pain intensity after thoracic surgery. Methods: Patients received either oral opioid analgesia (Opioid Group) or epidural analgesia and were then bridged to systemic opioid analgesia (EDA + O Group) in this retrospective observational study. Medical history, discharge letters, anesthetic protocols, and pain protocols were evaluated in 621 patients after open thoracotomy and assessed with a stepward back elimination in a multivariate logistic regression model. Results: Data of 621 thoracotomies in 2014 were analyzed, 309 patients in the Opioid Group and 312 patients in the EDA + O Group. Pain scores at rest and on coughing were significantly lower in the EDA + O Group on postoperative days (PODs) 1-4 (P < 0.001). Stepwise backward elimination in multivariate logistic regression identified preexisting pain disease (P = 0.034), no epidural analgesia (P < 0.001), opioids in preoperative pain therapy (P < 0.001), and antidepressant medication (P = 0.003) as independent risk factors for higher pain intensity at rest on PODs 1-4. Same on PODs 5-8 with regard to opioids in preoperative pain therapy (P < 0.001) and antidepressant medication (P = 0.018). Moreover, on PODs 5-8, male gender had a lower risk (P < 0.003) for pain, and preexisting musculosceletal disease had a lower risk for more postoperative pain (P = 0.009). On coughing, male gender and younger age proved to have a lower risk for postoperative pain on PODs 1-8 and on PODs 1-4, respectively. Opioids in preexisting pain therapy and antidepressant medication were identified as risk factors for pain on PODs 1-8 on coughing, and pain disease was identified as a risk factor for more pain on PODs 1-4 (P = 0.041). Moreover, preexisting cardiac disease indicated more pain on PODs 1-4 (P = 0.05), and musculoskeletal disease and neurological disease indicated more pain on PODs 5-8 (P = 0.041, and P = 0.023). Conclusions: We present data on independent risk factors for higher pain intensity during recovery after thoracotomy. The lack of postoperative epidural analgesia, female gender, preexisting opioid pain therapy, and chronic pain are the strongest risk factors for higher pain intensity. Antidepressant medication was identified as an independent risk factor at rest and on coughing on all PODs. Study limitations: The study design is retrospective.

Gynostemma pentaphyllum is neuroprotective in a rat model of cardiopulmonary resuscitation.

Asphyxial cardiac arrest (ACA)-induced ischemia results in acute and delayed neuronal cell death. The early reperfusion phase is critical for the outcome. Intervention strategies directed to this period are promising to reduce ACA/resuscitation-dependent impairments. This study focused on the evaluation of the protective potential of an extract from Gynostemma pentaphyllum (GP), a plant used in traditional medicine with antioxidative, glucose lowering and neuroprotective activities, in an ACA rat model. We tested the following parameters: i) Basic systemic parameters such as pCO2 and blood glucose value within the first 30 min post-ACA; ii) mitochondrial response by determining activities of citrate synthase, respiratory chain complexes I + III and II + III, and the composition of cardiolipin 6 and 24 h post-ACA; iii) neuronal vitality of the CA1 hippocampal region by immunohistochemistry 24 h and 7 days post-ACA; and iv) cognitive function by a novel object recognition test 7 days post-ACA. GP, administered after reaching spontaneous circulation, counteracted the following: i) ACA-mediated increases in arterial CO2 tension and blood glucose values; ii) transient increase in the activity of the respiratory chain complexes II + III; iii) elevation in cardiolipin content; iv) hippocampal CA1 neurodegeneration, and v) loss of normal novelty-object seeking. The protective effects of GP were accompanied by side effects of the vehicle DMSO, such as the stimulation of citrate synthase activity in control animals, inhibition of cardiolipin synthesis in ACA animals and complex II + III activity in both control and ACA animals. The results emphasize the importance of the early post-resuscitation phase for the neurological outcome after ACA/resuscitation, and demonstrated the power of GP substitution as neuroprotective intervention. Moreover, the results underline the need of a careful handling of the popular vehicle DMSO.

High-potential defense mechanisms of neocortex in a rat model of transient asphyxia induced cardiac arrest.

Cardiac arrest (CA) is a common cause of disability and mortality and thus an important risk for human health. Circulatory failure has dramatic consequences for the brain as one of the most oxygen-consuming organs. Hippocampus, striatum and neocortex rate among the most vulnerable brain regions. The neocortex is less sensitive to hypoxia/reperfusion in comparison with the hippocampal CA1 region. That implicates the existence of efficient defense mechanisms in the neocortex against hypoxia/reperfusion injury, which we analyzed in a well-established CA rat model. We explored different immunohistochemical markers (NeuN, MAP2, GFAP, IBA1, NOX4, MnSOD, Bax, caspase 3, cfos, nNOS, eNOS, iNOS, TUNEL), amount of mitochondria, activities of respiratory chain complexes and amount/composition of cardiolipin. CA induced a moderate degeneration of cortical neurons. As possible defense mechanisms the study revealed: (i) increased activities of respiratory chain complexes of cortical mitochondria as response to increased energy demand after ACA-induced cell stress; (ii) increase of cardiolipin content as cellular stress response, which might contribute to the promotion of mitochondrial ATP synthesis; (iii) strengthening of the fast, effective and long-lasting mitochondrial MnSOD defense system; (iv) ACA-induced increase in expression of eNOS and nNOS in vasculature being able to reduce ischemic injury by vasodilation.

The Influence of Type of Anesthesia, Perioperative Pain, and Preoperative Health Status on Chronic Pain Six Months After Thoracotomy-A Prospective Cohort Study.

BACKGROUND: Chronic post-thoracotomy pain (CPP) has a high incidence. However, less is known about risk factors and the influence of different analgesia therapies. METHODS: In this prospective cohort study, patients either received standardized epidural analgesia or began an oral analgesic protocol with controlled-release oxycodone immediately postoperatively. Patients answered a baseline questionnaire on the day before surgery and a follow-up questionnaire six months postoperatively. The questionnaire included Short-Form 12, the Neuropathic Pain Scale, and descriptive questions for CPP. Pain protocols of all patients were examined. Logistic regression was used to analyze the risk factors related to CPP. RESULTS: One hundred seventy-four patients were enrolled; data of 131 patients were available after the six-month follow-up period. Fifty-one patients (39%) had CPP six months postoperatively. Of these, more than 80% had impaired daily activity or ability to work, or reported sleeping disturbance due to CPP. The strongest predictive factors for the development of CPP were: thoracic pain for three months preoperatively (odds ratio [OR] = 3.54, 95% confidence interval [CI] = 1.69-7.40, P = 0.001), thoracic pain for 12 months preoperatively (OR = 2.73, 95% CI = 1.28-5.83, P = 0.009), and higher pain scores at rest in the first five postoperative days compared with patients without CPP (OR = 1.79, 95% CI = 1.24-2.57, P = 0.002). Neuropathic pain was present in 4.8% of patients. Patients with CPP had a reduced physical (P = 0.005) and mental health status (P = 0.03) six months after surgery compared with patients without CPP. CONCLUSIONS: Preoperative thoracic pain and higher pain scores in the first five postoperative days seem to be the strongest risk factors for the development of CPP. CPP patients reported poorer mental and physical health before and six months after surgery.

Anesthesia specific differences in a cardio-pulmonary resuscitation rat model; halothane versus sevoflurane.

OBJECTIVE: Our asphyxia cardiac arrest (ACA) rat model is well established. The original model was designed in the 1990th using halothane and nitrous oxide for pre-insult anesthesia. Because of its hepato-toxicity and its potential to induce severe liver failures, halothane is no longer used in clinical anesthesia for several years. In order to minimize the health risk for our laboratory staff as well as to keep the experimental settings of our model on a clinically oriented basis we decided to replace halothane by sevoflurane. In this study we intended to determine if the change of the narcotic gas regiment causes changes in the neurological damage and how far our model had to be adjusted. METHODS: Adult rats were subjected to 5min of ACA followed by resuscitation. There were four treatment groups: ACA - halothane, ACA - sevoflurane and with halothane or sevoflurane sham operated animals. Vital and blood parameters were monitored during the 45min post-resuscitation intensive care phase. After a survival time of 7 days histological evaluation of the hippocampus was performed. RESULTS: We observed that resuscitated rats anesthetized prior by sevoflurane (i) have had a lower heart rate and a higher MAP compared to halothane anesthetized animals; (ii) The neurological damaged were significantly reduced in the hippocampal CA1 region in sevoflurane treated rats. CONCLUSION: Using sevoflurane instead of halothane for anesthesia requires some physiological and experimental changes. However the model keeps its validity. Sevoflurane caused less pronounced neurodegeneration in the CA1 region of the hippocampus. This had to be considered in further resuscitation-studies containing sevoflurane as anesthetic. Institutional protocol number for animal studies: 42502-2-2-947 Uni MD.

[Sufficient high frequency jet ventilation during a period of 2.5 h - Airway management during resection of a tracheaesophageal fistula and tracheal resection]. / Kasuistik: Suffiziente High-Frequency-Jet-Ventilation über 2,5 h.

We present a 54 year old female patient who had undergone a Ross procedure in 2009, and in 2013 again a replacement of the aortic root and arch with bioprothetic material and homograft replacement of the pulmonalis walve. Postoperatively the patient had experienced a functional compromising tracheal stenosis and a persistent esophago-tracheal fistula. Endoscopic attempts to close the fistula were not successful, and the fistula was "bridged" with an endoscopically positioned tracheal stent.We report the anaesthesiological management during the open surgical repair of the esophago-tracheal fistula and resection of 2 tracheal rings with high frequency jet ventilation over a period of 2.5 h. The Patient was discharged from hospital on the 17. postoperative day.

[Management of anaesthesia and intensive care for acute ischemic insult]. / Ischämischer Insult - Anästhesiologisches und intensivmedizinisches Management.

The acute ischemic stroke (AIS) is a major cause of death and disability in Germany. The treatment of patients with AIS focuses on rapid recanalization of close brain vessels. Anaesthesiologists are likely to encounter patients with AIS and must be aware of the anaesthetic considerations for these patients. The advantage and risk of general anaesthesia during a neuroradiology procedure is shown. We make recommendations for blood pressure, blood glucose and temperature management.

Low-dose nitroglycerine improves outcome after cardiac arrest in rats.

OBJECTIVE: The aim of this study was to evaluate the outcome of intravenously applied nitroglycerine (NTG, 1µgkg(-1)min(-1) for 1h) after resuscitation from an asphyxia cardiac arrest (ACA) insult. We hypothesized that NTG infused for 1h after the return of spontaneous circulation (ROSC) would improve functional and neuro-morphological outcomes. METHODS: Adult rats were subjected to 8min of ACA followed by resuscitation. There were three treatment groups: ACA, ACA+NTG and sham operated. Vital and blood parameters were monitored during the 1h post-resuscitation intensive care phase. After survival times of 3, 6, 12, 24, 72h and 7 days, the neurological deficit score (NDS) was measured. Histological evaluation of the hippocampus, cortex, the thalamic reticular nucleus and the caudate-putamen was performed 7 days post insult. RESULTS: We found that NTG (i) induced significantly higher initial MAP peaks; (ii) resulted in a less-pronounced elevation of heart rates after ROSC with significantly faster normalization to baseline levels; and (iii) influenced glucose metabolism, temporarily elevating blood glucose to non-physiological levels. Even so, NTG (iv) improved the neurological outcome and (v) reduced neurodegeneration, mainly in the hippocampal CA1 region. A significant NTG-associated decrease in blood pressure did not occur. CONCLUSION: The effect of low-dosed NTG applied post-resuscitation appears to be neuroprotective, demonstrated by reduced hippocampal damage and a better NDS, even with temporarily elevated blood glucose to non-physiological levels. Thus, additional studies are needed to evaluate NTG-triggered mechanisms and optimized dosages before clinical translation should be considered. Animal study institutional protocol number: 42502-2-2-947-Uni-MD.

[Development of the physician based prehospital emergency medicine system in the former GDR]. / Entwicklung des Notarztwesens in Deutschland - Ostdeutschland.

The development of the physician based prehospital emergency medicine system of the former GDR started in the early 1960th. Initially the use of ambulances was trauma-orientated. Because of the increasing number for non-traumatic emergencies the so called SMH-system (emergency medical services) was stepwise established. The SMH-system consisted of two branches: the DMH for potentially life threatening emergencies and the DHD for urgent house visits. Parts of the system were also regional dispatch centers, a specific nationwide phone number (115), standardized equipment, and supervision by a physician. In addition regulations about documentation and staff-qualification were centrally installed.

Prolonged minocycline treatment impairs motor neuronal survival and glial function in organotypic rat spinal cord cultures.

BACKGROUND: Minocycline, a second-generation tetracycline antibiotic, exhibits anti-inflammatory and neuroprotective effects in various experimental models of neurological diseases, such as stroke, Alzheimer's disease, amyotrophic lateral sclerosis and spinal cord injury. However, conflicting results have prompted a debate regarding the beneficial effects of minocycline. METHODS: In this study, we analyzed minocycline treatment in organotypic spinal cord cultures of neonatal rats as a model of motor neuron survival and regeneration after injury. Minocycline was administered in 2 different concentrations (10 and 100 µM) at various time points in culture and fixed after 1 week. RESULTS: Prolonged minocycline administration decreased the survival of motor neurons in the organotypic cultures. This effect was strongly enhanced with higher concentrations of minocycline. High concentrations of minocycline reduced the number of DAPI-positive cell nuclei in organotypic cultures and simultaneously inhibited microglial activation. Astrocytes, which covered the surface of the control organotypic cultures, revealed a peripheral distribution after early minocycline treatment. Thus, we further analyzed the effects of 100 µM minocycline on the viability and migration ability of dispersed primary glial cell cultures. We found that minocycline reduced cell viability, delayed wound closure in a scratch migration assay and increased connexin 43 protein levels in these cultures. CONCLUSIONS: The administration of high doses of minocycline was deleterious for motor neuron survival. In addition, it inhibited microglial activation and impaired glial viability and migration. These data suggest that especially high doses of minocycline might have undesired affects in treatment of spinal cord injury. Further experiments are required to determine the conditions for the safe clinical administration of minocycline in spinal cord injured patients.

Spontaneous hypothermia is not able to completely counteract cardiac arrest-induced mitochondrial impairment in the rat heart.

Vijlbrief et al. [Neonatology 2012;102:243-248] reported a beneficial effect of hypothermia on cardiac function after perinatal asphyxia indicated by low levels of B-type natriuretic peptide (BNP). Elevated troponin I plasma levels, however, reflects impairment of cardiomyocytes under hypothermic conditions. The importance of BNP and cardiac troponin I as biomarkers of cardiac dysfunction that may supplement or substitute Doppler echocardiography has been outlined. Using an asphyxia cardiac arrest (ACA) animal model under spontaneous hypothermia, we found a decrease in the activities of NADH-cytochrome c-oxidoreductase and succinate-cytochrome c-oxidoreductase in comparison to normothermic sham-operated controls. This observation indicates the impairment of the respiratory chain of heart mitochondria, which is accompanied by morphological changes in these mitochondria. Changed cardiac troponin I levels and respiratory chain complexes activity represent different but corresponding steps within the process of cardiomyocyte injury. Interestingly, liver and brain mitochondria remained unchanged under this condition. Patients could benefit from the control of mitochondrial function during hypothermic intervention. When indicated, substances could be supplemented that support mitochondrial function, e.g. antioxidative-acting vitamins and ubiquinone.

Minocycline neuroprotection in a rat model of asphyxial cardiac arrest is limited.

OBJECTIVE: The study investigated a possible neuroprotective potency of minocycline in an experimental asphyxial cardiac arrest (ACA) rat model. Clinically important survival times were evaluated thus broadening common experimental approaches. METHODS: Adult rats were subjected to 5 min of ACA followed by resuscitation. There were two main treatment groups: ACA and sham operated. Relating to minocycline treatment each group consisted of three sub-groups: pre-, post-, and sans-mino, with three different survival times: 4, 7, and 21 days. Neurodegeneration and microgliosis were monitored by immunohistochemistry. Alterations of microglia-associated gene expression were analyzed by quantitative RT-PCR. RESULTS: ACA induced massive nerve cell loss and activation of microglia/macrophages in hippocampal CA1 cell layer intensifying with survival time. After 7 days, minocycline significantly decreased both, neuronal degeneration and microglia response in dependence on the application pattern; application post ACA was most effective. After 21 days, neuroprotective effects of minocycline were lost. ACA significantly induced expression of the microglia-associated factors Ccl2, CD45, Mac-1, F4-80, and Tnfa. Independent on survival time, minocycline affected these parameters not significantly. Expression of iNOS was unaffected by both, ACA and minocycline. CONCLUSIONS: In adult rat hippocampus microglia was significantly activated by ACA. Minocycline positive affected neuronal survival and microglial response temporary, even when applied up to 18 h after ACA, thus defining a therapeutically-relevant time window. As ACA-induced neuronal cell death involves acute and delayed events, longer minocycline intervention targeting also secondary injury cascades should manifest neuroprotective potency, a question to be answered by further experiments.

[Anaesthesia for interventional procedures]. / Anästhesie in der interventionellen Radiologie.

Interventional radiologists perform a wide range of procedures. The anaesthesiologist takes care for provision of a physiologically stable and immobile patient, alteration of arterial blood pressure as necessary, and appropriate and timely management of complications. In this article we discuss the anaesthetic considerations for procedures like embolization of arterio-venous malformations, coiling of cerebral aneurysms, kyphoplasty and vertebroplasty including the preprocedure preparation, monitoring requirements, suitable anaesthetic techniques, postprocedure management and complication.

Selection of reference genes for quantitative real-time PCR in a rat asphyxial cardiac arrest model.

BACKGROUND: Cardiac arrest, and the associated arrest of blood circulation, immediately leads to permanent brain damage because of the exhaustion of oxygen, glucose and energy resources in the brain. Most hippocampal CA1 neurons die during the first week post the insult. Molecular data concerning the recovery after resuscitation are sparse and limited to the early time period. Expression analysis of marker genes via quantitative real-time RT-PCR enables to follow up the remodeling process. However, proper validation of the applied normalization strategy is a crucial prerequisite for reliable conclusions.Therefore, the present study aimed to determine the expression stability of ten commonly used reference genes (Actb, actin, beta; B2m, beta-2 microglobulin;CypA, cyclophilin A; Gapdh, glyceraldehyde-3-phosphate dehydrogenase; Hprt, hypoxanthine guanine phosphoribosyl transferase; Pgk1, phosphoglycerate kinase 1; Rpl13a, ribosomal protein L13A; Sdha, succinat dehydrogenase complex, subunit a, flavoprotein (Fp); Tbp, TATA box binding protein; Ywhaz, tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, zeta polypeptide) in the rat hippocampus four, seven and twenty-one days after cardiac arrest. Moreover, experimental groups treated with the anti-inflammatory and anti-apoptotic drug minocycline have been included in the study as well. RESULTS: The microglial marker Mac-1, used as a target gene to validate the experimental model, was found to be upregulated about 10- to 20-fold after cardiac arrest. Expression stability of candidate reference genes was analyzed using geNorm and NormFinder software tools. Several of these genes behave rather stable. CypA and Pgk1 were identified by geNorm as the two most stable genes 4 and 21 days after asphyxial cardiac arrest, CypA and Gapdh at 7 days post treatment. B2m turned out to be the most variable candidate reference gene, being about 2-fold upregulated in the cardiac arrest treatment groups. CONCLUSION: We have validated endogenous control genes for qRT-PCR analysis of gene expression in rat hippocampus after resuscitation from cardiac arrest. For normalization purposes in gene profiling studies a combination of CypA and Pgk1 should be considered 4 and 21 days post injury, whereas CypA and Gapdh is the best combination at 7 days. CypA is most favorable if restriction to a single reference gene for all time points is required.

Oxyresveratrol (trans-2,3',4,5'-tetrahydroxystilbene) is neuroprotective and inhibits the apoptotic cell death in transient cerebral ischemia.

Oxidative stress is one of the major pathological factors in the cascade that leads to cell death in cerebral ischemia. Here, we investigated the neuroprotective effect of a naturally occurring antioxidant, oxyresveratrol, to reduce brain injury after cerebral stroke. We used the transient rat middle cerebral artery occlusion (MCAO) model of brain ischemia to induce a defined brain infarction. Oxyresveratrol was given twice intraperitoneally: immediately after occlusion and at the time of reperfusion. Oxyresveratrol (10 or 20 mg/kg) significantly reduced the brain infarct volume by approximately 54% and 63%, respectively, when compared to vehicle-treated MCAO rats. Also, the neurological deficits as assessed by different scoring methods improved in oxyresveratrol-treated MCAO rats. Histological analysis of apoptotic markers in the ischemic brain area revealed that oxyresveratrol treatment diminished cytochrome c release and decreased caspase-3 activation in MCAO rats. Also, staining for apoptotic DNA showed that the number of apoptotic nuclei in ischemic brain was reduced after oxyresveratrol treatment as compared to the vehicle-treated MCAO rats. This dose-dependent neuroprotective effect of oxyresveratrol in an in vivo stroke model demonstrates that this drug may prove to be beneficial for a therapeutic strategy to limit brain injury in acute brain ischemia.